Camera-projector matching using an unstructured video stream

This paper presents a novel approach for matching 2D points between a video projector and a digital camera. Our method is motivated by camera-projector applications for which the projected image needs to be warped to prevent geometric distortion. Since the warping process often needs geometric information on the 3D scene that can only be obtained from triangulation, we propose a technique for matching points in the projector to points in the camera based on arbitrary video sequences. The novelty of our method lies in the fact that it does not require the use of pre-designed structured light patterns as is usually the case. The back bone of our application lies in a function that matches activity patterns instead of colors. This makes our method robust to pose, to severe photometric and geometric distortions. It also does not require calibration of the color response curve of the camera-projector system. We present quantitative and qualitative results with synthetic and real life examples, and compare the proposed method with the scale invariant feature transform (SIFT) method and with a state-of-the-art structured light technique. We show that our method performs almost as well as structured light methods and significantly outperforms SIFT when the contrast of the video captured by the camera has been degraded.